Plant Diversity ›› 2024, Vol. 46 ›› Issue (04): 448-461.DOI: 10.1016/j.pld.2024.03.001

• Articles • Previous Articles    

Plastid phylogenomics provides new insights into the systematics, diversification, and biogeography of Cymbidium (Orchidaceae)

Hai-Yao Chena,b, Zhi-Rong Zhangc, Xin Yaoa,f, Ji-Dong Yac, Xiao-Hua Jind, Lin Wanga,f, Lu Lue, De-Zhu Lic, Jun-Bo Yangc, Wen-Bin Yua,f   

  1. a. Center for Integrative Conservation & Yunnan Key Laboratory for the Conservation of Tropical Rainforests and Asian Elephants, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China;
    b. University of Chinese Academy of Sciences, Huairou District, Beijing 101408, China;
    c. Plant Germplasm and Genomics Center, Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan 650201, China;
    d. State Key Laboratory of Plant Diversity and Specility Crops, Institute of Botany, Chinese Academy of Sciences, Haidian District, Beijing 100093, China;
    e. School of Pharmaceutical Sciences, Yunnan Key Laboratory of Pharmacology for Natural Products, and Yunnan College of Modern Biomedical Industry, Kunming Medical University, Kunming, Yunnan 650500, China;
    f. Southeast Asia Biodiversity Research Institute, Chinese Academy of Sciences, Yezin, Nay Pyi Taw 05282, Myanmar
  • Received:2023-08-17 Revised:2024-02-29 Published:2024-07-29
  • Contact: Jun-Bo Yang,E-mail:jbyang@mail.kib.ac.cn;Wen-Bin Yu,E-mail:yuwenbin@xtbg.ac.cn
  • Supported by:
    This study was supported by grants from the Strategic Priority Research Program of the Chinese Academy of Sciences (XDB31000000), The 14th Five-Year Plan of the Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences (XTBG-1450101), the Science and Technology Basic Resources Investigation Program of China (2021FY100200), the Key Basic Research Program of Yunnan Province, China (202101BC070003), and the Yunnan Revitalization Talent Support Program “Young Talent” and "Innovation Team" Projects, and Ecological and Environmental Conservation Program from the Department of Ecology and Environment of Yunnan Province.

Abstract: Cymbidium (Orchidaceae: Epidendroideae), with around 60 species, is widely-distributed across Southeast Asia, providing a nice system for studying the processes that underlie patterns of biodiversity in the region. However, phylogenetic relationships of Cymbidium have not been well resolved, hampering investigations of species diversification and the biogeographical history of this genus. In this study, we construct a plastome phylogeny of 56 Cymbidium species, with four well-resolved major clades, which provides a framework for biogeographical and diversification rate analyses. Molecular dating and biogeographical analyses show that Cymbidium likely originated in the region spanning northern Indo-Burma to the eastern Himalayas during the early Miocene (~21.10 Ma). It then rapidly diversified into four major clades in East Asia within approximately a million years during the middle Miocene. Cymbidium spp. migration to the adjacent regions (Borneo, Philippines, and Sulawesi) primarily occurred during the Pliocene-Pleistocene period. Our analyses indicate that the net diversification rate of Cymbidium has decreased since its origin, and is positively associated with changes in temperature and monsoon intensity. Favorable hydrothermal conditions brought by monsoon intensification in the early Miocene possibly contributed to the initial rapid diversification, after which the net diversification rate was reduced with the cooling climate after the middle Miocene. The transition from epiphytic to terrestrial habits may have enabled adaptation to cooler environments and colonization of northern niches, yet without a significant effect on diversification rates. This study provides new insights into how monsoon activity and temperature changes affected the diversification dynamics of plants in Southeast Asia.

Key words: Cymbidium, East Asia, Asian monsoons, Climate change, Biogeographical patterns